From ddbd4558271fad4dfa24935f2eddeac287e91c99 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Zoe=20=E2=9C=A8?=
 <87827343+zoeisnowooze@users.noreply.github.com>
Date: Fri, 6 Aug 2021 12:56:27 -0400
Subject: [PATCH] Add statistics support for the PVOutput sensor (#54149)

---
 homeassistant/components/pvoutput/sensor.py | 42 ++++++++++++++++++++-
 1 file changed, 40 insertions(+), 2 deletions(-)

diff --git a/homeassistant/components/pvoutput/sensor.py b/homeassistant/components/pvoutput/sensor.py
index 5744dbfff9a..305615e4b2c 100644
--- a/homeassistant/components/pvoutput/sensor.py
+++ b/homeassistant/components/pvoutput/sensor.py
@@ -1,7 +1,10 @@
 """Support for getting collected information from PVOutput."""
+from __future__ import annotations
+
 from collections import namedtuple
-from datetime import timedelta
+from datetime import datetime, timedelta
 import logging
+from typing import cast
 
 import voluptuous as vol
 
@@ -9,6 +12,7 @@ from homeassistant.components.rest.data import RestData
 from homeassistant.components.sensor import (
     DEVICE_CLASS_ENERGY,
     PLATFORM_SCHEMA,
+    STATE_CLASS_MEASUREMENT,
     SensorEntity,
 )
 from homeassistant.const import (
@@ -22,6 +26,8 @@ from homeassistant.const import (
 )
 from homeassistant.core import callback
 import homeassistant.helpers.config_validation as cv
+from homeassistant.helpers.restore_state import RestoreEntity
+from homeassistant.util import dt as dt_util
 
 _LOGGER = logging.getLogger(__name__)
 _ENDPOINT = "http://pvoutput.org/service/r2/getstatus.jsp"
@@ -68,12 +74,15 @@ async def async_setup_platform(hass, config, async_add_entities, discovery_info=
     async_add_entities([PvoutputSensor(rest, name)])
 
 
-class PvoutputSensor(SensorEntity):
+class PvoutputSensor(SensorEntity, RestoreEntity):
     """Representation of a PVOutput sensor."""
 
+    _attr_state_class = STATE_CLASS_MEASUREMENT
     _attr_device_class = DEVICE_CLASS_ENERGY
     _attr_unit_of_measurement = ENERGY_WATT_HOUR
 
+    _old_state: int | None = None
+
     def __init__(self, rest, name):
         """Initialize a PVOutput sensor."""
         self.rest = rest
@@ -120,8 +129,37 @@ class PvoutputSensor(SensorEntity):
         await self.rest.async_update()
         self._async_update_from_rest_data()
 
+        new_state: int | None = None
+        state = cast("str | None", self.state)
+        if state is not None:
+            new_state = int(state)
+
+        did_reset = False
+        if new_state is None:
+            did_reset = False
+        elif self._old_state is None:
+            did_reset = True
+        elif new_state == 0:
+            did_reset = self._old_state != 0
+        elif new_state < self._old_state:
+            did_reset = True
+
+        if did_reset:
+            self._attr_last_reset = dt_util.utcnow()
+
+        if new_state is not None:
+            self._old_state = new_state
+
     async def async_added_to_hass(self):
         """Ensure the data from the initial update is reflected in the state."""
+        last_state = await self.async_get_last_state()
+        if last_state is not None:
+            if "last_reset" in last_state.attributes:
+                self._attr_last_reset = dt_util.as_utc(
+                    datetime.fromisoformat(last_state.attributes["last_reset"])
+                )
+            self._old_state = int(last_state.state)
+
         self._async_update_from_rest_data()
 
     @callback